This invention pertains to a wheel lock assembly, particularly a manually actuated wheel lock assembly used on wheelchairs, patient transports, strollers, carts, and the like. For example, large diameter wheels on wheelchairs often include a wheel lock that is typically a four bar linkage assembly. An actuating handle is used in a push-to-lock or a pull-to-lock arrangement to selectively move or pivot a shoe into selective engagement with the periphery of a pneumatic, solid, or semi-solid tire mounted on the wheel. The shoe is actuated or pressed into the outer surface of the tire, slightly deforming it to provide sufficient holding force against rotation.
Known four bar linkage assemblies, however, require a number of components or parts. For example, four fasteners are often used to interconnect the links and include individual bearings associated with each fastener to provide selective movement between the link arms of the linkage assembly. This large number of components becomes labor intensive to manufacture, even though some of the assembly operations may be automated.
Moreover, the action of these prior art wheel lock assemblies is not as smooth as desired. Pin joint problems are often associated with the four bar linkage assembly and, in addition to the difficulties of assembly, is not easy to adjust. The articulating points between the separate links also present a number of potential pinch points where an operator's fingers can be inadvertently pinched.
Further, this type of conventional wheel lock assembly is not conducive to alternative mounting arrangements, different size wheelchairs, nor does it maintain the maximum holding pressure once it passes the over-center position. Rather, a four bar linkage assembly has a decreased holding force once it passes the over-center position. This conventional wheel lock design is also not easily converted between push-to-lock and pull-to-lock arrangements.
Thus, the present invention is deemed to meet these and other objectives that overcome the various problems noted above.